Having both admined for ETF2L and organised LANs, I do not think ETF2L should necessarily adjust its map pool because of the LAN in Poland. Autumn season has always been the one where you can go a little crazy with maps because there usually aren't any LANs directly after. Not to hate on the PoLANd event, but I don't think it is that household name yet. If they were to do it leading up to insomnia, it would be a whole different debate...
For CPH Games and RCADIA we have usually simply gone with the most recent ETF2L map pool so people could scrim the maps in the season and perform at LAN. Now, I get that this might be not a popular decision with two new maps in the mix, but it is a possibility.